The present invention relates to a bin for use in a mail sorting apparatus, and more particularly to such a bin having a new and improved damping means to prevent noise and vibration.
Mail sorting apparatus, such as those currently in use by the United States Post Office, employ bins or carts that are supported on rollers and travel through the sorting system on tracks. Each bin includes a plurality of parallel vertical slots. Mail is deposited in the slots through their respective open top ends. As the bin passes over a location corresponding to the destination of a letter contained therein, a pivotably movable door that closes the bottom of the slot is opened, thus allowing the mail carried in that slot to drop.
When a door is allowed to open under the force of the associated spring, the resulting metal-on-metal impact causes a loud unpleasant noise. Moreover, vibrations are produced within the bin that loosen screws and cause maintenance problems. Since each mail sorting system includes many such bins each having a plurality of doors closing at a rapid rate, the noise and maintenance problems are severe.
A solution to the above problem that has been partially implemented by the United States Post Office utilizes a tab extending from one end of each door. The door, including the tab, forms a flat planar object. Notches are cut in a side wall of the bin to permit each tab to extend to the exterior thereof. The tabs are held between two torsion springs that damp vibrations and noise when the door slams shut. The springs associated with each door are carried by an arm supported by the axle about which an adjacent door is pivotable. Of course, the arm for the last door of the bin must be supported by a pin provided specifically for that purpose.